Charge rollers (CRs) are used to charge a photoconductor in hard imaging systems (e.g., laser-printer imaging systems). Similar to Scorotron/Corona charging, charge rollers use air ionization to charge a photoconductor. However, a charge roller has increased charging efficiency (close to 100% charging efficiency) and uses lower voltages (˜1500V) compared with Scorotron charging (˜6500V). Physical contact of a charge roller with a photoconductor may cause print quality defects that are mainly driven by the interaction of the charge roller with materials remaining on the photoconductor after cleaning operations of the photoconductor. Materials remaining on the photoconductor may create sticky polymers which coat the photoconductor. These interactions are even more intensive with liquid electrophotographic processes where, after cleaning the photoconductor, imaging oil comprising dissolved materials and charge directors may still be present on the photoconductor surface giving rise to several print quality issues.
In general, a charge roller contacting a photoconductor may interact with a remaining image formed on the photoconductor, thereby creating ghosting effects (e.g., with the circumference of the charge roller). Further, the charge roller contacting the photoconductor may also interact with other materials (e.g., imaging oil) that remain on the photoconductor, contaminate the photoconductor with leak materials (e.g., conductive ions from the charge roller rubber), and create pin holes in the photoconductor in the charge roller/photoconductor nip. The above drawbacks may contribute to photoconductor quality issues by interfering with the photoconductor/blanket image transfer, interfering with image development, and interfering with cleaning of the photoconductor. The above drawbacks may also cause problems relating to photoconductor lateral conductivity, and uneven photoconductor charging. As a result, lifetime of consumables may decrease and the printing cost per page may increase. Other problems with liquid electrophotographic processes using a photoconductor with a seam area include print quality defects due to accumulation of imaging fluid in defects or wrap-over sections (e.g., seam regions) on the photoconductor. Movement of the charge roller over a section of the photoconductor may elevationally attract some of the accumulated materials and duplicate them into an image area. The extra imaging oil may not only cause disturbance of normal imaging processes but also cause disruption of the Paschen curve and the photoconductor charging voltages, thereby leading to permanent photoconductor damage.